1. Field of the Invention
The present invention relates to a turbocharger including a bearing configured to receive thrust load.
2. Description of the Related Art
Turbochargers have been conventionally known in which a turbine shaft is rotatably supported by a bearing housing with a turbine impeller provided to one end of the turbine shaft, and with a compressor impeller provided to the other end of the turbine shaft. This turbocharger is connected to an engine. The turbine impeller is rotated by an exhaust gas discharged from the engine. The rotation of the turbine impeller is transmitted to the compressor impeller via the turbine shaft, and the compressor impeller is thus rotated. Thereby, the turbocharger compresses air with the rotation of the compressor impeller, and supercharges the engine with the compressed air.
A bearing configured to pivotally support the turbine shaft is provided inside the bearing housing. While supporting the turbine shaft, the bearing receives radial load and thrust load. Lubricant is supplied to the interstice between an end surface of the bearing in an axial direction of the turbine shaft and, for example, a thrust collar opposed to the end surface. It is not easy, however, for the lubricant to reach the interstice without any arrangements, because the thrust load makes the bearing and the thrust collar hit each other. In a turbocharger described in Japanese Patent Application Laid-open Publication No. 2007-23858 (PTL 1), multiple grooves in which lubricant flows are provided to an end surface of a bearing to come into contact with a thrust collar, in such a way as to radially extend in radial directions of the bearing.